breaker melted

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electricalist

Senior Member
Location
dallas tx
After a storm . Just information. A customer at some point said he has lost some power at his house.
200 a panel outside on pole feeds 200 a mbp inside through feed through lugs.
Bryant panel. The 60 amp breaker that feeds electric heat was burnt from one phase to another
It didn't trip.. Burnt til it didn't work
Any clues
 

LEO2854

Esteemed Member
Location
Ma
After a storm . Just information. A customer at some point said he has lost some power at his house.
200 a panel outside on pole feeds 200 a mbp inside through feed through lugs.
Bryant panel. The 60 amp breaker that feeds electric heat was burnt from one phase to another
It didn't trip.. Burnt til it didn't work
Any clues

Loose connections.

Water got into the panel somehow and the busing corroded causing the breaker to heat up.
 

kwired

Electron manager
Location
NE Nebraska
After a storm . Just information. A customer at some point said he has lost some power at his house.
200 a panel outside on pole feeds 200 a mbp inside through feed through lugs.
Bryant panel. The 60 amp breaker that feeds electric heat was burnt from one phase to another
It didn't trip.. Burnt til it didn't work
Any clues
What was burned? The bus connection area or the output lug area?

High enough resistance fault (typically because of conductive/semi conductive contaminants being present) may present a situation where some pretty impressive arcing can occur, yet current levels never reach instantaneous trip levels of the device protecting - which would be the 200 amp breaker if on the bus side of your breaker in question. This happens much easier with 480/277 then with 240-208/120.
 

electricalist

Senior Member
Location
dallas tx
The 60 amp breaker for the heat unit burned.. Till the breaker was no longer making contact.
I would want this type of event to trip. But it didnt have arc fault breakers.
There was a #4 ground in the panel. I didnt see any ground rod but there was a # 4 ground coming up from the ground going up the pole the service panel and meter base were on and it had a split bolt where the ground split and went into the meter base and the other connected ground went up to far to tell where..
Out of the meter to service panel was a ground and neutral. Couldnt open the meter but I think the trailer needed a ground rod, and an egc with the feeders that was bonded at the service panel.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
The 60 amp breaker for the heat unit burned.. Till the breaker was no longer making contact.
I would want this type of event to trip. But it didnt have arc fault breakers.
Poor or high resistance connections produce excessive heat without drawing high currents so the breaker is may not trip. AFCIs do not detect or react to heat producing high resistance connections.
There was a #4 ground in the panel. I didnt see any ground rod but there was a # 4 ground coming up from the ground going up the pole the service panel and meter base were on and it had a split bolt where the ground split and went into the meter base and the other connected ground went up to far to tell where.
Out of the meter to service panel was a ground and neutral. Couldnt open the meter but I think the trailer needed a ground rod, and an egc with the feeders that was bonded at the service panel.
The connection to earth has nothing to do with breaker tripping or not tripping.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
a few comments...
I am in complete agreement with don in post #6.

From your "The 60 amp breaker for the heat unit burned.. Till the breaker was no longer making contact."
it sounds like there was a poor connection where the breaker plugged onto the buss.
A common occurrence. When you replace the breaker check the buss carefully. It would be a good idea to move the new breaker if possible.

From you "but I think the trailer needed a ground rod, and an egc with the feeders that was bonded at the service panel. "
The feeder from the service panel to the trailer panel by Code would need an EGC"
 

kwired

Electron manager
Location
NE Nebraska
From your "The 60 amp breaker for the heat unit burned.. Till the breaker was no longer making contact."
it sounds like there was a poor connection where the breaker plugged onto the buss.
A common occurrence. When you replace the breaker check the buss carefully. It would be a good idea to move the new breaker if possible.
I will put emphasis on check the bus carefully, if it heated enough to melt the breaker, the bus likely got pretty hot as well and possibly is compromised in more then just the space(s) that particular breaker was connected to. If it is discolored beyond the connection point of that melted breaker you should be replacing the panel, or at least swapping new loadcenter interior it is one that is still made to fit in same way.
 
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